4 ms·

How does this compare to something like move-shoot-move? I think that one costs only $200. Is it even worth it to DIY.

dylan604 5y ago
Shoot-move-shoot does what it sounds like. It moves the platform, allows time for the movement to settle, snaps the shot, then moves again. Astrotrackers like this are constantly moving at the same rate that the earth spins on its axis. This allows for the subject to remain in the same poistion in the frame during super long exposures. Depending on the accuracy of the polar alignment and the focal length of the lens, tracking allows for shots to go from <20 seconds to multiple minutes long for one exposure.
- andrewxdiamond 5y ago
  What is the benefit of using robotics to move the camera over image stabilization software in post? Is it simply image quality? Or are there more trade offs?
  - dukeofdoom 5y ago
    You need a long exposure to let in enough light for stars to become clearly visible. If you expose for longer than ~ 30 seconds, then the earth will rotate enough to start causing star trails. This will physically rotate the camera to counteract earths rotation.
  - dylan604 5y ago
    The is a common question, but there are certain things that are just better done in camera than post. Then there are situations where a combination of in camera + post provides optimum results. Astrophotography is one that can and does use both. The longer you can expose, the more information obtained. For ultimate long shots, you need to compensate for the earth's rotation. You continue to snap away all night, and then take those images into post where you stack the images. The stacking software adds the data together resulting in a single image that is the equivalent of a single image with an exposure time equaling the sum of each shot. Why do this? If you do single long exposure, there is a very good chance your image will have an airplane fly through, a satellite streak by, or something more terrestrial like a fellow stargazer shining a laser through your frame, car headlights, etc. Taking a series of short exposures limits those issues, and if it happens, you throw out that shot and only loose 45-60 seconds instead of 15 minutes. Stacking can also use shots you take when the lens is covered called dark frames. You take this for the same exposure time as the normal shots. This provides a noise pattern that builds up in any electronic sensor as the heat builds up from staying energized for so long (as well as natural summertime heat). That noise pattern can then be subtracted by the stacking software. The stacking software can also realign the images so you can use shots from multiple shoot days (er, nights).
    - spfzero 5y ago
      Taking short exposures and stacking also can help by removing the effects of periodic error in the mount gear-train (or belt-train).
- dukeofdoom 5y ago
  I'm not sure if that is correct. It says on their website it's a start tracker. https://www.moveshootmove.com/ https://www.moveshootmove.com/
  - sdfsfsrgg 5y ago
    It can do both. They seem to use the product's name ("move-shoot-move") to refer to a mode which both tracks the stars and moves independently, creating a panning timelapse.
  - dylan604 5y ago
    Interesting. I didn't realize there was a product/company with that name. Shoot-move-shoot is a common saying in motion controlled photography, and that was what I described. I love the age we're in where anybody with a little know how can cheaply/affordably build something that was only available to the very well funded before. Each one of these are attempting the same thing, but trying to avoid the pain points each dev has seen from other products.
- dheera 5y ago
  Their marketing is a little dishonest though. https://i.imgur.com/QD32T7r.png https://i.imgur.com/QD32T7r.png They show all the other trackers with an Alt-Az wedge, but show their tracker without that piece, to make the other trackers look big. With the specific 2 other trackers pictured, you can detach that wedge and use them exactly like the MSM tracker without their Alt-Az mounts and they would be a lot smaller. Personally I own a SkyGuider Pro and use it with a pan-tilt head tripod and no wedge.
  - dylan604 5y ago
    Haha, I noticed the same thing. I've started watching some of their tutorial videos, and have some other nit picking comments as well. However, these will probably get someone that's never done astrophotography up and running with the ability to get some great shots totally unachievable 15 years ago in this price range.
- LeifCarrotson 5y ago
  One benefit of shoot-move-shoot is that when combining/compositing the images together in post, you can remove and adjust for temporary artifacts like satellites or terrestrial lighting that would otherwise ruin a long exposure. You can also compensate for motion platform inaccuracies by shifting the location of each layer to keep the object you're trying to image at the same location in the frame. Minutes-long exposures mean you're just ORing all the photons together, and you get what you get.
  - astroflask 5y ago
    For sufficiently dim targets, you absolutely need minutes long exposure. If you go for shorter bursts, you face two main challenges: 1) Not enough photons reach the sensor to distinguish the object you are trying to photograph from the noise floor of the sensor. This is by far the biggest reason to go for a tracking mount. 2) You bog your computer down in post processing. 50x1 minute images are far simpler to align than 500x6 seconds images. Combine (1) and (2), and there's barely any reason to go for untracked shots. As for satellites, planes, clouds, or other kind of transient phenomena that can potentially ruin a shot, that's where you apply some kind of clipping over data (usually sigma clipping or some variation of it) and problem solved.
dheera 5y ago
Almost everything is cheaper to buy than to DIY. This is a hacker forum and people like to DIY for other reasons than cost, including customization, the learning experience of building something yourself, being fully FOSS, not waiting for long lead times in some locations, and other reasons.

Shoot-move-shoot does what it sounds like. It moves the platform, allows time for the movement to settle, snaps the shot, then moves again. Astrotrackers like this are constantly moving at the same rate that the earth spins on its axis. This allows for the subject to remain in the same poistion in the frame during super long exposures. Depending on the accuracy of the polar alignment and the focal length of the lens, tracking allows for shots to go from <20 seconds to multiple minutes long for one exposure.

andrewxdiamond 5y ago
What is the benefit of using robotics to move the camera over image stabilization software in post? Is it simply image quality? Or are there more trade offs?
- dukeofdoom 5y ago
  You need a long exposure to let in enough light for stars to become clearly visible. If you expose for longer than ~ 30 seconds, then the earth will rotate enough to start causing star trails. This will physically rotate the camera to counteract earths rotation.
- dylan604 5y ago
  The is a common question, but there are certain things that are just better done in camera than post. Then there are situations where a combination of in camera + post provides optimum results. Astrophotography is one that can and does use both. The longer you can expose, the more information obtained. For ultimate long shots, you need to compensate for the earth's rotation. You continue to snap away all night, and then take those images into post where you stack the images. The stacking software adds the data together resulting in a single image that is the equivalent of a single image with an exposure time equaling the sum of each shot. Why do this? If you do single long exposure, there is a very good chance your image will have an airplane fly through, a satellite streak by, or something more terrestrial like a fellow stargazer shining a laser through your frame, car headlights, etc. Taking a series of short exposures limits those issues, and if it happens, you throw out that shot and only loose 45-60 seconds instead of 15 minutes. Stacking can also use shots you take when the lens is covered called dark frames. You take this for the same exposure time as the normal shots. This provides a noise pattern that builds up in any electronic sensor as the heat builds up from staying energized for so long (as well as natural summertime heat). That noise pattern can then be subtracted by the stacking software. The stacking software can also realign the images so you can use shots from multiple shoot days (er, nights).
  - spfzero 5y ago
    Taking short exposures and stacking also can help by removing the effects of periodic error in the mount gear-train (or belt-train).
dukeofdoom 5y ago
I'm not sure if that is correct. It says on their website it's a start tracker. https://www.moveshootmove.com/ https://www.moveshootmove.com/
- sdfsfsrgg 5y ago
  It can do both. They seem to use the product's name ("move-shoot-move") to refer to a mode which both tracks the stars and moves independently, creating a panning timelapse.
- dylan604 5y ago
  Interesting. I didn't realize there was a product/company with that name. Shoot-move-shoot is a common saying in motion controlled photography, and that was what I described. I love the age we're in where anybody with a little know how can cheaply/affordably build something that was only available to the very well funded before. Each one of these are attempting the same thing, but trying to avoid the pain points each dev has seen from other products.
dheera 5y ago
Their marketing is a little dishonest though. https://i.imgur.com/QD32T7r.png https://i.imgur.com/QD32T7r.png They show all the other trackers with an Alt-Az wedge, but show their tracker without that piece, to make the other trackers look big. With the specific 2 other trackers pictured, you can detach that wedge and use them exactly like the MSM tracker without their Alt-Az mounts and they would be a lot smaller. Personally I own a SkyGuider Pro and use it with a pan-tilt head tripod and no wedge.
- dylan604 5y ago
  Haha, I noticed the same thing. I've started watching some of their tutorial videos, and have some other nit picking comments as well. However, these will probably get someone that's never done astrophotography up and running with the ability to get some great shots totally unachievable 15 years ago in this price range.
LeifCarrotson 5y ago
One benefit of shoot-move-shoot is that when combining/compositing the images together in post, you can remove and adjust for temporary artifacts like satellites or terrestrial lighting that would otherwise ruin a long exposure. You can also compensate for motion platform inaccuracies by shifting the location of each layer to keep the object you're trying to image at the same location in the frame. Minutes-long exposures mean you're just ORing all the photons together, and you get what you get.
- astroflask 5y ago
  For sufficiently dim targets, you absolutely need minutes long exposure. If you go for shorter bursts, you face two main challenges: 1) Not enough photons reach the sensor to distinguish the object you are trying to photograph from the noise floor of the sensor. This is by far the biggest reason to go for a tracking mount. 2) You bog your computer down in post processing. 50x1 minute images are far simpler to align than 500x6 seconds images. Combine (1) and (2), and there's barely any reason to go for untracked shots. As for satellites, planes, clouds, or other kind of transient phenomena that can potentially ruin a shot, that's where you apply some kind of clipping over data (usually sigma clipping or some variation of it) and problem solved.

dheera 5y ago

Almost everything is cheaper to buy than to DIY. This is a hacker forum and people like to DIY for other reasons than cost, including customization, the learning experience of building something yourself, being fully FOSS, not waiting for long lead times in some locations, and other reasons.